Apparatus for controlling the transfer of seismic data from magnetic tape storage to a photographic recording

Claim 1

In a seismic data processing system for photographically reproducing seismic data from a plurality of seismic channels including a multiplexer for successively applying seismic data for each of said plurality of seismic channels to a cathode-ray tube to successively intensity modulate the electron beam one time during each sweep of the electron beam across the face of said cathode-ray tube for each of said seismic channels, a timing line generator for applying timing line modulation signals to said cathode-ray tube, a timing number generator for applying timing number modulation signals to said cathode-ray tube, a trace mark generator for providing seismic trace centerline modulation signals to said cathode-ray tube, an annotation generator for applying alphanumeric modulation signals to said cathode-ray tube, and a drum plotter for photographically reproducing in a side-by-side relationship each sweep of said electron beam, the combination therewith of: a. a computer, b. a first command generated by said computer selecting the drum position at which the sweep of the electron beam of the cathode-ray tube is to be triggered, c. means for producing a drum position signal representative of the rotational position of said drum plotter, d. means for comparing said drum position signal with said first command and for triggering the sweep of the cathode-ray tube when the drum is in the rotational position selected by said sweep command, e. a second command generated by said computer selecting the rotational speed of said drum plotter and the data rate at which said cathode-ray tube is to be modulated by said seismic data, f. a decoder which converts said second command into a drum speed control signal and a data rate control signal, g. means for applying said drum speed control signal to said drum plotter to control its rotational speed, h. means responsive to said data rate control signal for controlling the rate at which said seismic data is applied to said multiplexer so that each sweep of the cathode-ray tube is modulated with the seismic data one time for each of said plurality of seismic traces during each revolution of said drum plotter, and i. means for selectively enabling said timing line generator, said timing number generator, said trace mark generator, and said annotation generator to modulate the electron beam sweep of said cathode-ray tube whereby said seismic data is photographically recorded on said drum plotter in a plurality of parallel and continuous seismic traces along with timing lines, timing numbers to identify selected timing lines, centerline marking of selected seismic traces, and annotation data.